"MCU firmware not genuine

A couple of days ago Immediately upon plugging in my Nano S into the laptop “MCU firmware not genuine” appearec on the screen, I.then removed it and put it back in it reacted normally, and asking for my pin number. This happened a few times over the course of a day and makes me think it may have been hacked although no funds have gone missing. Since then I have only used my second Nano S, several times over and the message hasn’t occurred. I feel It might be that the first device was faulty, but the words “not genuine” conotate with “fake” or “hack” so now I am worried. I would be grateful for your opinion.

I can understand your concern here! Apparently this is quite a common issue when updating the Ledger, at least with version 1.4.1. Check which version of firmware you’re running by connecting the Ledger then going to the settings app. Navigate to Settings > Device > Firmware and check the version there. If it’s 1.4.1 or lower, then I wouldn’t worry about the message too much. It is worth updating however, see Ledger’s support page for help with performing an update: